For far too long, those who oppose gun reforms have said that nothing can be done to stem the violence.
Those claims are demonstrably wrong. Research on gun violence is notoriously underfunded, but the data we do have shows that lawmakers can act to save lives from gun violence.
Thousands of people will descend on the Mall this week to protest gun violence in the United States. This movement should be informed by science, with specific policy proposals that could make a real impact.
 1:25
Opinion | President Trump, you can do much more to reduce gun deaths
Opinion | The Washington Post Editorial Board appeals to Trump and Congress to stand up to the gun lobby and prevent mass shootings. 
  
Ban weapons of war
The Las Vegas massacre. The massacre at the Pulse nightclub in Orlando. The movie theater shooting in Aurora, Colo. The Virginia Tech slaughter. The massacre at the Texas First Baptist Church.
These are the five highest-casualty mass shootings in modern American history. And what did they all have in common? Semiautomatic weapons that allowed the shooter to fire into crowds without reloading.
Based on the evidence we have, banning these weapons probably won’t do too much to curb overall gun deaths. We know this because in 1994, Congress passed legislation to outlaw the sale of certain types of semiautomatic guns and large-capacity magazines, and the effect was unimpressive. Gun homicide rates declined during the ban, but they also fell after the ban expired in 2004. One federally funded study of the ban found that the effect on violence was insignificant, partly because it was full of loopholes.
Mass shooting fatalities in the U.S.
Before assault
weapons ban
Assault
weapons ban
After assault
weapons ban
120
fatalities
100
80
60
40
20
0
1968-1994
1995-2004
2005-2018
Death tolls include victims killed by shooters within a day of the main shooting, including any who were killed in another way. Totals also include people who later died from injuries received during the shootings. 2018 data through March 21.
THE WASHINGTON POST
Source: Mother Jones; Washington Post mass shooting database
But banning so-called assault weapons was never meant to reduce overall gun deaths. It was meant to reduce gun deaths from mass shootings — even if these represent a small portion of gun violence.
And in fact, mass shooting casualties dipped during the ban, although a review of studies by the Rand Corporation found the effect of the ban on mass shootings to be inconclusive. We need to know more. 
But research shows that semiautomatic weapons and weapons with high-capacity magazines are more dangerous than other weapons in shooting events. One older study of handgun attacks in New Jersey shows that gunfire incidents involving semiautomatic weapons wounded 15 percent more people than shootings with other weapons. Another more recent study from Minneapolis found that shootings with more than 10 shots fired accounted for between 20 and 28 percent of gun victims in the city.
So how do we keep such dangerous weapons from being used in crime? A ban on assault weapons might help, as data from a few cities during the 1994 ban suggest:
Assault weapons as a share of guns recovered by police at crime scenes
Before assault
weapons ban
After assault
weapons ban
Milwaukee 5.9%
4.9% Milwaukee 
Anchorage 3.6%
Miami 2.5%
Boston 2.2%
2.1% Anchorage
Baltimore 1.9%
1.7% Miami
St. Louis 1.3%
1.3% Baltimore
0.9% St. Louis
0.6% Boston
Time periods for data for each city vary based on when data was collected.
THE WASHINGTON POST
Source: Christopher Koper, 2004 National Institute of Justice study
But experts say focusing on reducing large-capacity magazines might be more effective. Simply put, gunmen are less deadly when they have to reload.
Such a ban might take time to have an effect, as a Post investigation shows. But it would be worth it. Alarmingly, local crime data suggest that crimes committed with high-powered weapons have been on the rise since the 1994 ban ended.
Again, mass shootings account for a small piece of the puzzle, so any ban on these weapons and magazines would result in marginal improvements, at best. But even if this step reduced shootings by 1 percent — far less than what the Minneapolis study suggests — that would mean 650 fewer people shot a year. Isn’t that worth it?
  
Keep guns away from kids
Recently, we’ve heard proposals to raise age limits for semiautomatic weapons. Taken alone, this would do very little. Since 2009, men under 21 committed two mass shootings with semiautomatic rifles. And one of those shootings involved a gun purchased illegally.
But expanding existing age limits to all guns might be more effective, since young people are far more likely to commit homicide than older ones. One survey of inmates found that setting a minimum age requirement of 21 could have prohibited gun possession in 17 percent of cases in which people legally owned a gun and used it to commit a crime.
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Of course, keeping guns out of the hands of young shooters would be difficult, because it’s so easy for people to obtain guns illegally. But age limits in general have proven to be effective in limiting bad behavior, so it’s worth trying.
There’s another reform that could be even more effective at keeping guns from kids: requiring gun owners to securely store firearms in a locked container or with a tamper-resistant mechanical lock.
Nearly 2 million minors in the United States live in homes where firearms are loaded and easy to access. And alarmingly, one study found that of the teens who had guns in their home who had attempted suicide in the past year, 40 percent had easy access to the firearm. Another study from the federal government shows that 68 percent of school shootings are perpetrated by shooters who obtain a gun from their homes or the homes of relatives.
In Massachusetts, which has the strictest safe-storage laws in the country, guns are used in just 9 percent of youth suicides, compared with 42 percent nationally. The suicide death rate among youth in the state is 38 percent below the national average.
Youth suicides by gun
Number per 100,000 people
2000-2016
2
4
6
8
NH
WA
VT
ME
MT
ND
OR
MA
MN
ID
WI
NY
RI
SD
WY
MI
CT
PA
IA
NJ
NE
NV
NV
OH
IL
IN
DE
UT
CO
WV
CA
MD
VA
KS
MO
KY
NC
TN
OK
AZ
AZ
AR
SC
NM
GA
MS
AL
LA
TX
States with some form of safe storage law
AK
FL
HI
THE WASHINGTON POST
Source: Giffords Law Center
The Giffords Law Center to Prevent Gun Violence also reports that states requiring locks on handguns in at least some circumstances have 40 percent fewer suicides per capita and 68 percent fewer firearm suicides per capita than states without such laws.
Meanwhile, another safety innovation is being developed: smart guns. These are guns that use fingerprint recognition and other means so that only their owners can fire them. The technology is still relatively new, but it’s promising. One small study found that over seven years, 37 percent of gun deaths could have been prevented by smart guns. Lawmakers could encourage their use by incorporating them into laws regulating safe storage.
  
Stop the flow of guns
Here’s a general rule: The more guns there are, the more gun deaths there will be.
It holds across countries (note how much the United States stands out):
Homicide rates versus gun ownership among 
developed countries
3.0
United States
2.5
Homicide by firearm rate per 100,000 people
2.0
1.5
1.0
Switzerland
Italy
Finland
0.5
Australia
Japan
0.0
0
20
40
60
80
100
Average firearms per 100 people
THE WASHINGTON POST
Source: United Nations
And across states. One 2013 study from Boston University found that for every percentage point increase in gun ownership at the state level, there was a 0.9 percent rise in the firearm homicide rate.
So how do we reduce the steady flow of guns? Three ideas:
1. Institute a buyback program
In the 1990s, Australia spent $500 million to buy back almost 600,000 guns. Harvard University researchers found that the gun homicide rate dropped 42 percent in the seven years following the law and the gun suicide rate fell 58 percent.
An Australian study found that for every 3,500 guns withdrawn per 100,000 people, the government was able to achieve a 74 percent drop in gun suicides.
In fact, since the ban, the country has not experienced another mass shooting. That doesn’t proves causation. But the likelihood it’s due to chance? Roughly 1 in 200,000, according to a recent paper.
Of course, the United States is different from Australia. The Australian buyback was mandatory, which would probably run into constitutional problems here. Plus, we have way more guns per capita, so the United States would have to spend exponentially more to make a significant difference.
Still, given Australia’s trends, it’s worth at least experimentation. Perhaps the government can use buyback programs to target specific kinds of weapons, such as semiautomatic weapons and large-capacity magazines.
2. Limit the number of guns people can buy at one time 
Federal gun enforcers have long warned that state laws allowing bulk purchases of guns enable crime. Older studies from what is now called the Bureau of Alcohol, Tobacco, Firearms and Explosives show that as many as 1 in 5 handguns recovered in a crime were originally purchased as part of a sale in which multiple guns were purchased.
To combat this behavior, some states have instituted “one handgun a month” policies, such as Virginia in 1993. At the time, Virginia was the top supplier of guns seized in the Northeast. Three years later, the state dropped to eighth. Research also shows that the Virginia law was effective in reducing criminal firearms sent to nearby states. It also led to a 35 percent reduction in guns recovered anywhere in the United States that were traced back to Virginia.
Such a policy isn’t going to solve gun trafficking. The Virginia law didn’t prevent “straw purchases” in which traffickers pay people to buy guns legally so they can be sold elsewhere. In fact, Virginia remained the eighth-top supplier of illegal guns even after it repealed its one-handgun-a-month law in 2012.
But experts say one-gun-a-month laws make it more costly for criminals to traffic guns. And given the success in the past, such policies are worth promoting.
3. Hold gun dealers accountable
Research has shown that in some cities, guns used to commit crimes often come from a small set of gun dealers. In Milwaukee, for example, a single dealer was linked to a majority of the guns used in the city’s crime.
So how do we stop the flow of those guns? Hold dealers accountable.
In 1999, the federal government published a report identifying gun shops connected with crime guns, including that Milwaukee dealer. In response to negative publicity, that dealer changed its sales practices. Afterward, the city saw a 76 percent reduction in the flow of new guns from that shop to criminals and a 44 percent reduction in new crime guns overall. But in 2003, Congress passed a law prohibiting the government from publishing such data, after which the rate of new gun sales from that dealer to criminals shot up 200 percent.
Studies show that regulation of licensed dealers — such as record-keeping requirements or inspection mandates — can also reduce interstate trafficking. So can litigation against gun dealers that allow their guns to enter criminal markets. One sting operation conducted by New York City reduced the probability of guns from the dealers they targeted ending up in the hands of criminals by 84 percent.
  
Strengthen background checks
Federal law requires background checks to obtain a gun, but those checks are extremely porous.
Under federal law, only licensed gun dealers have to perform these background checks. Private individuals and many online retailers don’t. That leaves a lot of gun owners — about 42 percent, according to one survey published in 2017 — who didn’t undergo a background check for a gun purchase. So what happens when states go beyond federal laws and require all handgun sales to undergo a background check? Fewer gun deaths.
Between 2009 and 2012, those states had 35 percent fewer gun deaths per capita than those without the requirement. Those states also have 53 percent fewer firearm suicides and 31 percent fewer overall suicides per capita.
Firearm deaths
Number per 100,000 people
2016
5
10
15
20
NH
WA
VT
ME
MT
ND
OR
MA
MN
ID
WI
NY
RI
SD
WY
MI
CT
PA
IA
NJ
NE
NV
OH
IL
IN
DE
UT
CO
WV
CA
MD
VA
KS
MO
KY
NC
TN
OK
AZ
AZ
AR
SC
NM
GA
MS
AL
LA
TX
States with some form
of expanded background checks
AK
FL
HI
States are categorized from highest rate to lowest rate. Although adjusted for differences in age distribution and population size, rankings by state do not take into account other state-specific population characteristics that may affect the level of mortality. When the number of deaths is small, rankings by state may be unreliable due to volatility in death rates.
THE WASHINGTON POST
Source: Centers for Disease Control and Prevention
That doesn’t prove causation. In fact, a few states with expanded background checks have relatively high gun-death rates.
But we do know most gun offenders obtain their weapons through unlicensed sellers. One survey of state prison inmates convicted of offenses committed with guns in 13 states found that only 13 percent obtained their guns from a seller that had to conduct a background check. Among those who were supposed to be prohibited from possessing a firearm, nearly all of them got their hands on one through suppliers that didn’t have to conduct a background check. Closing that loophole might help, although it’s questionable to what degree, since black markets already feed the flow of crime.
What else can we do to strengthen background checks? Three possibilities:
1. Close the “Charleston Loophole”
Most gun background checks are instant. But some — around 9 percent — take more time, and federal law says if it takes more than three business days, the sale can proceed. As a result, thousands of people who were not supposed have access to guns ended up getting them, as the Government Accountability Office reported.
Among the people who benefited from this loophole? Dylann Roof, who killed nine people in Charleston, S.C., in 2015. Ending this practice would save lives.
2. Close the “Boyfriend Gap”
Between 2006 and 2014, an average of 760 Americans were killed with guns annually by their spouses, ex-spouses or dating partners, according to an Associated Press analysis.
Federal law prevents anyone with domestic violence misdemeanors from having a gun, but that law is defined narrowly and doesn’t include all domestic violence perpetrators — for example, boyfriends. More specifically, the law doesn’t keep guns from abusers who are not married, do not live with their partner or do not share a child with them.
Some states have expanded on federal law — and it works. One study found that domestic-violence-related homicide rates decline 7 percent after a state passes such laws.
3. Implement waiting periods
It’s not clear that waiting periods reduce violent crime. But we’re pretty sure they prevent suicides.
Research shows that people who buy handguns are at higher risk of suicide within a week of the purchase, and that waiting periods can keep them from using guns to commit suicide. In fact, one study found that when South Dakota repealed its 48-hour waiting period in 2012, suicides jumped 7.6 percent in the following year.
4. Improve reporting on mental health
Mental illness is associated with a relatively small portion (around 5 percent) of gun homicides. Federal law already prohibits anyone committed to a mental-health facility or deemed dangerous or lacking all mental capacities through a legal proceeding from having a gun.
But mental-health records are notoriously spotty. There’s limited evidence that improved reporting at the state level might reduce violent crimes. Connecticut started reporting mental-health data to the National Instant Criminal Background Check System in 2007, and one study found that violent crimes committed by people with mental illness there significantly decreased.
We can also make it easier for family members to help loved ones with mental illness, by letting them seek court orders to disarm relatives who might do harm to themselves. In Connecticut, which has allowed this since 1999, one study estimates that the law averted 72 suicide attempts through 2013 from being fatal.
  
Treat guns like we treat cars
Consider two data points: first in Connecticut, then in Missouri.
In Connecticut, state lawmakers required people to get a license and safety training for a gun, just as we do for cars. In the decade after, it saw a drop in both gun homicides and suicides — at faster rates than other states without similar laws. And at the same time, Connecticut saw no significant drop in homicides not related to guns.
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In Missouri, the state legislature repealed its licensing requirements in 2007. 
A study found that the law change was associated with an additional 55 to 63 homicides in each of the five years following the repeal — even as homicides committed without guns dropped.
In both cases, it’s hard to prove a connection. But these experiences do strongly suggest something we learned in our decades-long efforts to reduce vehicle-related deaths: Regulation saves lives.
It can also deter crime. Research from the advocacy group Mayors Against Illegal Guns has found that guns sold in states with licensing laws — which are sometimes paired with mandatory registration of guns with local police — end up being exported for criminal activity at one-third the rate of states without the laws.
Why? Because it’s much harder to feed guns into illegal markets if police can trace them to their legal gun owners. After Missouri repealed its licensing laws, police in Iowa and Illinois started reporting an increase in Missouri guns showing up at crime scenes.
About this story
Illustration by Ann Telnaes. Design and development by Andrew Braford.